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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Stressreaktionsprofil und -determinanten bei simulierten Notfallsituationen in einem Full-Scale-Simulator: Effekte unterschiedlicher Kontrollierbarkeit / Stress reaction profile and determinants at simulated emergency situations in a full scale simulator: Effects of different controllability

Ringleb, Matthias 12 June 2012 (has links)
In der Anästhesiologie ist die Nutzung sog. Full-Scale-Simulatoren in der Aus- und Weiterbildung inszwischen etabliert. Bisher weitgehend ungenutzt ist dieses Setting zur Untersuchung habitueller und situationaler Faktoren im Zusammenhang mit Stressreaktionen sowie der Leistungen, die Trainierende hier zeigen. Der Fokus der vorliegenden Arbeit liegt auf dem Konzept der Kontrolle. Dabei werden ausgewählte habituelle Persönlichkeitsmerkmale (Studie 1) untersucht. Zudem wird die situative Kontrollierbarkeit von Narkosekomplikationen experimentell variiert (Studie 2): Gemäß der Theorie der gelernten Hilflosigkeit führt Unkontrollierbarkeit (im Vergleich zu Kontrollierbarkeit) von Ereignissen erhöhter Stressbelastung (im Sinne eines emotionalen und somatischen Defizits) und zu Leistungsreduzierungen (im Sinne eines kognitiv-assoziativen Defizits). Teilnehmer der Studien waren Medizinstudierende im Praktischen Jahr mit Wahlfach Anästhesiologie, wobei das Geschlecht als quasiexperimenteller Faktor berücksichtigt wurde. In Studie 1 durchliefen 34 Probanden (16 Frauen und 18 Männer) in gegenbalancierter Reihenfolge eine Ruhe-, eine Standardlaborstress- und eine Simulationsbedingung. Die Simulationsbedingung umfasste ein Notfallszenario mit einer Phase des Kammerflimmerns. Während dieser Phase wurde die medizinische (Reanimations-)Leistung anhand der Richtlinien des Europäischen Fachrates für Wiederbelebung evaluiert (Nolan et al., 2005). Der Standardlaborstress bestand aus einer Rede vor einer Videokamera. Die psychische Stressreaktion (mittels visueller Analogskalen) und endokrine Stressreaktion (per Speichelcortisol) wurde in allen Bedingungen zu sieben Messzeitpunkten erfasst. In der vorliegenden Arbeit wurde bezüglich Studie 1 die Teilfragestellung untersucht, welche Zusammenhänge zwischen habituellen Persönlichkeitsmerkmalen und der medizinischen Leistung sowie der psychischen bzw. endokrinen Stressreaktion in der Simulationsbedingung auftreten. Als habituelle Variablen wurden allgemeine Kontrollüberzeugungen (mittels Fragebogen zu Kompetenz- und Kontrollüberzeugungen [FKK]; Krampen, 1991) und für die Anästhesie spezifische Kontrollüberzeugungen (mittels Anästhesie-spezifischer Kontroll-überzeugungen [SKÜ]; unveröffentlichter Fragebogen) erfasst: Diese generalisierten Erwartungen betreffen den Glauben einer Person, bedeutsame Ereignisse in ihrem Leben selbst beeinflussen zu können (Internalität), bzw. äußeren Kräften, wie anderen Personen (soziale Externalität) oder dem Schicksal (fatalistische Externalität), ausgeliefert zu sein. Außerdem wurden kontrollorientierte Copingstrategien, d. h. Stressbewältigungsversuche durch Veränderung der Situation, der eigenen Reaktion oder Selbstinstruktionen (mittels Stressverarbeitungsfragebogen [SVF]; Janke et al., 1985) erhoben. Die medizinische Leistung korrelierte wie folgt mit den habituellen Variablen: Allgemeine und spezifische fatalistische Externalität korrelierten in der Gesamtgruppe (Frauen und Männer) signifikant negativ mit der medizinischen Leistung (jeweils p < 0.05). Bei Frauen war die negative Korrelation zwischen allgemeiner fatalistischer Externalität und der Leistung ebenfalls signifikant (p < 0.01). Außerdem ergaben sich für die Copingstrategien durchweg negative Korrelationen mit der medizinischen Leistung: In Bezug auf die Copingstategien „Situationskontrolle – SVF“ und „Reaktionskontrolle – SVF“ waren diese Korrelationen für die Gesamtgruppe signifikant (jeweils p < 0.05). Bei Männern korrelierte die „Positive Selbstinstruktion – SVF“ signifikant negativ mit der medizinischen Leistung (p < 0.05). Die medizinische Leistung wurde dabei im Rahmen einer multiplen Regressionsanalyse durch die Kombination von anästhesie-spezifischer fatalistischer Externalität und der Copingstrategie „Situationskontrolle – SVF“ vorhergesagt (p < 0.01). Hinsichtlich der Korrelation zwischen der psychischen Stressreaktion und den habituellen Variablen zeigte sich eine Geschlechtsdifferenzierung: Bei Frauen war das „Selbstkonzept eigener Fähigkeiten – FKK“ negativ und die allgemeine „Fatalistische Externalität – FKK“ positiv mit dem Anstieg im psychischen Stressmaß korreliert (jeweils p < 0.05). Bei Männern hingegen trat zwischen der „Reaktionskontrolle – SVF“ und dem Anstieg im psychischen Stressmaß eine negative Korrelation auf (p < 0.01). Zwischen den habituellen Variablen und der endokrinen Stressreaktionen wurden keine signifikanten Assoziationen festgestellt. In Studie 1 konnten erstmals in einem anästhesiologischen Simulationssetting substantielle Zusammenhänge zwischen habituellen Variablen, die mit dem Konzept der Kontrolle assoziiert sind, und medizinischer Leistung sowie psychischer Stressreaktion festgestellt werden. Diese Zusammenhänge legen nahe, in Trainingsmaßnahmen in Full-Scale-Simulatoren zukünftig Module zur Modifikation von Kontrollüberzeugungen (insbesondere fatalistischer Externalität) – und damit zur Leistungsförderung – zu integrieren. Durch die Erhebung habitueller Variablen könnte das Training individuell an die jeweilige Persönlichkeit des Trainierenden angepasst werden. Angesichts der negativen Assoziationen zwischen den betrachteten Copingstrategien und der medizinischen Leistung sollten zukünftig solche negativ assoziierten Copingstrategien modifiziert und auch Strategien identifiziert werden, die in anästhesiologischen Notfallsituationen eher leistungsförderlich sind. In Studie 2 durchliefen 24 Medizinstudierende (12 Männer, 12 Frauen) jeweils eine von zwei Versuchsbedingungen. Erneut wurden zu sieben Messzeitpunkten die psychische und endokrine Stressreaktion erfasst. Die Probanden hatten an Tag 1 („Trainingsphase“) entweder durch ihre Interventionen Kontrolle über den medizinischen Zustand des simulierten Patienten bei der Behandlung auftretender Narkosekomplikationen (Kontrollierbar) oder aber die Ereignisse waren unkontrollierbar und durch das Verhalten des Joch-Kontrollpartners der Kontrollierbarkeitsgruppe determiniert (Unkontrollierbar). Tag 2 („Testphase“) beinhaltete ein weiteres simuliertes Notfallszenario mit Kontrollierbarkeit für beide Versuchsgruppen, wobei neben der psychischen und endokrinen Stressreaktion die medizinische Leistung in einem Reanimationsszenario (analog zum Vorgehen in Studie 1) erfasst wurde. Infolge der Vorerfahrung von unkontrollierbaren (verglichen mit kontrollierbaren) Narkosekomplikationen war die medizinische Leistung in der Testphase in der Gesamtgruppe entgegen der Erwartung höher (und nicht geringer). Eine große Effektstärke belegte, dass dieser Effekt insbesondere bei Männern auftrat. In der psychischen Stressreaktion trat für die Gesamtgruppe in der Testphase ein tendenziell höherer Ausgangswert nach Unkontrollierbarkeit (im Sinne eines emotionalen Defizits) auf (p < 0.10). Dies war primär auf die Frauen zurückzuführbar, bei denen ein signifikanter Effekt vorlag (p < 0.05). Auch im endokrinen Stressmaß war der Ausgangswert in der Testphase nach Unkontrollierbarkeitserfahrung (im Sinne eines somatischen Defizits) für die Gesamtgruppe tendenziell höher (p < 0.10). Der Anstieg im Cortisol fiel infolge der Vorerfahrung von Unkontrollierbarkeit nur bei Frauen tendenziell höher aus (p < 0.10). In Hinblick auf die Veränderungen im Cortisolanstieg von der Trainingsphase zur Testphase ergaben sich unterschiedliche Ergebnismuster für Frauen und Männer: Bei Frauen nahmen die Cortisolanstiege von Trainings- zu Testphase unter der Bedingung Kontrollierbar ab und unter der Bedingung Unkontrollierbar zu, bei Männern zeigte sich das umgekehrte Muster (jeweils p < 0.05). Diese Interaktion (Versuchsbedingung x Geschlecht) erwies sich als signifikant (p < 0.01). Es konnte erstmals für ein anästhesiologisches Setting gezeigt werden, dass die Vorerfahrung von Kontrollierbarkeit vs. Unkontrollierbarkeit signifikante Transfereffekte hervorruft. Der leistungsförderliche Effekt von Unkontrollierbarkeit könnte in Simulatortrainings genutzt werden, sofern er sich in weiteren Studien als stabil erweist. In Hinblick auf die Folgen von Erfahrungen im (simulierten) Operationssaal ist gleichzeitig zu berücksichtigen, dass erfahrene Unkontrollierbarkeit im Hinblick auf emotionale und somatische Hilflosigkeitsdefizite stresserhöhend wirkt. Die Daten liefern ferner erste Hinweise darauf, dass die Effekte von Unkontrollierbarkeit vs. Kontrollierbarkeit in einem Full-Scale-Simulator auf die Stressreaktionen in nachfolgenden kontrollierbaren Transfersituationen bei Männern und Frauen unterschiedlich ausfallen. Diese Ergebnisse sollten in Folgeuntersuchungen an größeren Stichproben repliziert und erweitert werden. Die vorliegende Arbeit erbrachte für den Simulationsbereich neue Erkenntnisse: Mit dem Konzept der Kontrolle assoziierte habituelle Variablen sind sowohl mit Leistungs- als auch Stressindikatoren in einem OP-Setting verbunden. Die situative – hier experimentell variierte – Kontrollierbarkeit wirkt sich auf diese Indikatoren aus. Daraus ergeben sich ggf. Möglichkeiten, Aus- und Weiterbildungsangebote in Full-Scale-Simulatoren einerseits individuell an die Teilnehmerpersönlichkeit anzupassen. Andererseits könnten Lernerfolge von Trainingsmaßnahmen durch die gezielte Schaffung situativer Kontrollierbarkeit optimiert werden.
42

Learned Helplessness and Depression: Comparison of Skilled Nursing and Assisted Living Facilities

Susic, Paul Lynn 01 January 2015 (has links)
Research with geriatric populations suggests high levels of clinical depression and greater financial and psychological costs of treatment in long-term care facilities with more restrictive care. Research on learned helplessness, a construct separate from depression, suggests learned helplessness and perceived control are useful theories for the study of elder depression, but the relationship between depression and learned helplessness in this population is not clear. This cross-sectional quantitative study examined the relationship between depression and learned helplessness by comparing residents over age 65 in less restrictive assisted living (n =42) versus those in more restrictive skilled nursing facilities (n =63). Data were collected using the Geriatric Depression Scale, the Helplessness subscale of the Cognitive Distortion Scales, and the Learned Helplessness and Instrumental Helplessness subscales of the Multi-Score Depression Inventory. Between-group ANOVA results confirmed a higher level of depression and state learned helplessness, but not trait learned helplessness, in restrictive skilled nursing residents when compared to those in less restrictive assisted living residents. There were positive correlations between learned helplessness, instrumental helplessness, and depression regardless of level of nursing care, and a positive correlation between perceived control and depression regardless of level of facility care. Identifying state learned helplessness and depression in long-term, restrictive care facilities can promote positive social change through increased awareness, intervention, and treatment to improve individual quality of life and maximize internalization of perceived control of the decision making process for elders.
43

Metacognitive intervention for the alleviation of learned helplessness

Helena Soares, Elza 11 December 2012 (has links)
The goal of this study was to investigate if participation in collaborative professional development workshops - on learned helplessness, self-efficacy, and metacognition - would impact teachers' beliefs in their capacity to address students' helplessness. The underlying assumption was that, with deeper understanding of the theoretical background upon which instructional practices should be constructed, teachers would develop a stronger belief that, through their pedagogical practices, they could impact students' individual learning outcomes as well as the classroom environment. In order to achieve this endeavor, an eight-week intervention was conducted in a low-achieving and low SES public school in Rio de Janeiro, Brazil. The study's design, development, implementation, and evaluation were oriented by guidelines derived from the formative and design experiment methodology. The study benefited from quantitative and qualitative data collection and analysis methods. Triangulation of data showed strong consistency between quantitative and qualitative findings. After the intervention, participating teachers acknowledged implementing the theories in their classrooms. Reported impacts included (a) strengthened teachers' beliefs about their capacity for effective teaching in this school environment; (b) increases in teachers' instructional efficacy and metacognitive abilities; (c) increased capacity to exercise reflective practice through evidence- based self-evaluations; (d) increased capacity to create comprehensive lesson plans including the Nine Events of Instruction (Gagne, 1985), the MUSIC Model of Academic Motivation (Jones, 2009), and metacognitive strategies (Schraw, 1998). As teachers implemented the strategies in their classes, they reported positive impacts on the students' interests, attitudes towards classroom activities, and efforts to achieve. / Ph. D.
44

Anxiety and depression in children and adolescents: an examination of cognition and attributional style

Byrd, Devin A. 04 March 2009 (has links)
The relationship of attributional style to anxiety and depression in children and adolescents has received little attention in comparison to studies conducted with adult populations. However, preliminary studies suggest that children and adolescents evidence similar attributional style patterns to those expressed by adults. This study further examines the relationship of anxiety and depression to attributional style to determine the utility and applicability of the adult model to children and adolescents. In addition, this study examines the accuracy of obtaining attributional style ratings using hypothetical events (i.e., questionnaire method) versus real-life events. Further, this study was designed to study the relationship of emotional measures of anxiety and depression (Le., Children's Depression Inventory and Revised Children's Manifest Anxiety Scale) versus cognitive measures of anxiety and depression (Negative Affect Self-Statement Questionnaire). It was hypothesized that real life events (as measured by the Specific Life Events Schedule; SLES) would prove to be a concurrently valid measure of attributional style in relation to hypothetical events presented through a questionnaire method (as measured by the Children's Attributional Style Questionnaire; CASQ). As well, it was predicted that real life events of the SLES would prove to be a more accurate measure of attributional style than hypothetical life events of the CASQ, in relation to achieved depression scores. Furthermore, it was predicted that certain indices of attributional style and negative self-statements would prove to be significant predictors of depression (as measured by the CDI) and anxiety scores (as measured by the RCMAS). / Master of Science
45

The Effects of Locus of Control and Soluble Discrimination Problems on Intelligence Test Performance

Smith, Alvin, active 1976- 12 1900 (has links)
This study investigated the possible differential effects of a series of soluble discrimination problems on internal versus external locus of control subjects. It was hypothesized that externals exposed to a series of discrimination problems would perform better on a test task than external controls, while internals exposed to the same problems would not perform better on the test task relative to their controls. As anticipated, the internals were not affected by the discrimination problems. However, contrary to expectations, the externals were not facilitated by exposure to the soluble problems. Since many external subjects failed to solve all of the soluble problems, a facilitative effect may depend upon the problems being solved.
46

Learned Helplessness in Rats: The Effects of Electroconvulsive Shock in an Animal Model of Depression

Thrasher, Ronald Keith 08 1900 (has links)
The response deficit following exposure to inescapable shock has been termed "learned helplessness." This experiment was designed (a) to determine whether learned helplessness following an inescapable footshock induction procedure extends to 48 hours, and (b) to test the hypothesis that electroconvulsive shock (ECS) reverses learned helplessness in rats. Subjects were tested for helplessness in a bar-press shock-escape task. Results indicated that helplessness was not present 48 hours after exposure to inescapable shock. A slight indication of helplessness was observed in the first 10 trials of the 60-trial task. In addition, ECS was shown to enhance performance in the test task; however, this facilitation effect was seen only in control animals that were not previously exposed to inescapable footshock.
47

Learned Helplessness, Locus of Control, and Academic Achievement

Mount, Suzanne Amidon 08 1900 (has links)
To determine the relationship among learned helplessness, locus of control, and academic achievement, data from 86 sixth graders were gathered and intercorrelated. Contingency of teacher-administered rewards and punishments as perceived by school children, and helpless behavior of students as judged by their teachers were measured. The Children's Nowicki-Strickland Locus of Control Scale was used to measure locus of control orientation. A positive relationship between academic achievement and locus of control was found. The contingency of reward scale was found to be predictive of academic achievement and helpless behavior. Virtually no significant relationships were found between any of the other variables and the contingency of punishment scale. Helpless behavior was found to be predictive of low academic success and an external locus of control.
48

Investigação longitudinal dos efeitos de diferentes contingências com estímulos apetitivos e aversivos sobre o desamparo aprendido / Longitudinal research on the effects of different contingencies with appetitive and aversive stimuli upon learned helplessness

Emileane Costa Assis de Oliveira 12 December 2007 (has links)
A hipótese do desamparo aprendido foi apresentada por Seligman & Maier em 1976 com uma suposta generalidade para todas as condições de estímulo, aversivos ou não e também como um modelo explicativo para a depressão humana. Esta proposição permitiu algumas manipulações experimentais no sentido de reverter o efeito do desamparo, utilizando, inclusive, reforçamento positivo na fase de \"terapia\". A partir dessas questões, o presente trabalho investigou: (a) se animais que apresentaram desamparo em teste de fuga também apresentam dificuldade de aprendizagem reforçada positivamente, envolvendo ou não controle de estímulos; (b) se a exposição ao reforço positivo elimina o desamparo e (c) se o desamparo interfere na resistência à mudança, medida sobre uma segunda aprendizagem discriminativa, reforçada positivamente, que envolve inversão do controle de estímulos. Ratos foram expostos a choques controláveis (C), incontroláveis (I) ou nenhum choque (N), e posteriormente submetidos ao teste de fuga. Foram selecionados três grupos (n=4) de animais que apresentaram desamparo (grupo I) ou aprendizagem de fuga no teste (grupos C e N). Em seguida, todos foram submetidos a (1) reforçamento positivo da resposta de pressão à barra (modelagem, CRF e 10 sessões de treino discriminativo FR/extinção), (2) re-teste de fuga, (3) 10 sessões de treino discriminativo com inversão dos estímulos sinalizadores. Outros quatro animais receberam apenas as sessões de reforçamento positivo. Obteve-se que todos os sujeitos aprenderam igualmente a discriminação e sua reversão, e que 3/4 dos animais do grupo I mantiveram o desamparo no segundo teste de fuga. Esses resultados indicam que o desamparo não se generalizou para a aprendizagem reforçada positivamente e que a exposição ao reforçamento positivo não aboliu o desamparo para a maioria dos sujeitos. Os dados foram discutidos considerando-se o efeito seletivo do desamparo, que ocorre apenas frente a algumas contingências, mas não a todas. Quanto ao fato da \"terapia\" com reforço positivo não ter modificado a dificuldade de aprender uma resposta mediante reforçamento negativo isso sugere que, se o desamparo decorre da aprendizagem de impossibilidade de controle sobre o ambiente, essa aprendizagem não abrange todos os estímulos do ambiente de forma generalizada, mas apenas a uma (ou algumas) determinada classe de estímulos. A identificação das características que definem essa(s) classe (ser choque, ser aversivo ou outras) também deve ser objeto de futuras investigações. / The learned helplessness hypothesis was put forward by Seligman & Maier in 1976 under the assumption of generality among all stimulus conditions, aversive or otherwise, and as an explanatory model of human depression. This proposition allowed for some experimental manipulations aimed at reversing the effect, using, among others things, positive reinforcement during a \"therapy\" phase. With that in mind, the present research attempted to investigate whether: (a) animals that showed signs of helplessness in an escape test also show a learning deficit with positive reinforcement, whether or not involving stimulus control; (b) the exposure to positive reinforcement may cancel out helplessness and (c) helplessness interferes with resistance to change, measured during a second, positively reinforced, discrimination learning (reversal). Rats were first exposed to controllable (C), uncontrollable (I) or no shocks (N) and then to an escape test. Three groups (n=4) were selected: one that displayed helplessness (group I) and two that learned to escape (groups C and N). After that, all subjects were exposed to (1) positive reinforcement of lever pressing (shaping, CRF and ten sessions of discrimination between FR and extinction), (2) the same escape test, (3) ten sessions of discrimination learning with reversed discriminative stimuli. Other four animals were exposed only to sessions of positive reinforcement. All animals learned discrimination and reversal, and three out of four animals of group I remained helplessness in the second escape test. These results suggest that helplessness did not generalize to a positively reinforced task and that exposure to positive reinforcement did not cancel out helplessness for most subjects. Results are discussed considering the selective effect of helplessness, which occurs under some conditions, but not under all. The fact that therapy with positive reinforcement did not reduce the learning deficit observed with negative reinforcement suggest that if helplessness result from learning that it is impossible to control the environment, this knowledge does not include all stimuli in a generalized manner, but only one (or some) certain stimuli class. The identification of the characteristics that define these classes (electric shocks, aversive stimuli, among others) should also be the purpose of future research.
49

Investigação longitudinal dos efeitos de diferentes contingências com estímulos apetitivos e aversivos sobre o desamparo aprendido / Longitudinal research on the effects of different contingencies with appetitive and aversive stimuli upon learned helplessness

Oliveira, Emileane Costa Assis de 12 December 2007 (has links)
A hipótese do desamparo aprendido foi apresentada por Seligman & Maier em 1976 com uma suposta generalidade para todas as condições de estímulo, aversivos ou não e também como um modelo explicativo para a depressão humana. Esta proposição permitiu algumas manipulações experimentais no sentido de reverter o efeito do desamparo, utilizando, inclusive, reforçamento positivo na fase de \"terapia\". A partir dessas questões, o presente trabalho investigou: (a) se animais que apresentaram desamparo em teste de fuga também apresentam dificuldade de aprendizagem reforçada positivamente, envolvendo ou não controle de estímulos; (b) se a exposição ao reforço positivo elimina o desamparo e (c) se o desamparo interfere na resistência à mudança, medida sobre uma segunda aprendizagem discriminativa, reforçada positivamente, que envolve inversão do controle de estímulos. Ratos foram expostos a choques controláveis (C), incontroláveis (I) ou nenhum choque (N), e posteriormente submetidos ao teste de fuga. Foram selecionados três grupos (n=4) de animais que apresentaram desamparo (grupo I) ou aprendizagem de fuga no teste (grupos C e N). Em seguida, todos foram submetidos a (1) reforçamento positivo da resposta de pressão à barra (modelagem, CRF e 10 sessões de treino discriminativo FR/extinção), (2) re-teste de fuga, (3) 10 sessões de treino discriminativo com inversão dos estímulos sinalizadores. Outros quatro animais receberam apenas as sessões de reforçamento positivo. Obteve-se que todos os sujeitos aprenderam igualmente a discriminação e sua reversão, e que 3/4 dos animais do grupo I mantiveram o desamparo no segundo teste de fuga. Esses resultados indicam que o desamparo não se generalizou para a aprendizagem reforçada positivamente e que a exposição ao reforçamento positivo não aboliu o desamparo para a maioria dos sujeitos. Os dados foram discutidos considerando-se o efeito seletivo do desamparo, que ocorre apenas frente a algumas contingências, mas não a todas. Quanto ao fato da \"terapia\" com reforço positivo não ter modificado a dificuldade de aprender uma resposta mediante reforçamento negativo isso sugere que, se o desamparo decorre da aprendizagem de impossibilidade de controle sobre o ambiente, essa aprendizagem não abrange todos os estímulos do ambiente de forma generalizada, mas apenas a uma (ou algumas) determinada classe de estímulos. A identificação das características que definem essa(s) classe (ser choque, ser aversivo ou outras) também deve ser objeto de futuras investigações. / The learned helplessness hypothesis was put forward by Seligman & Maier in 1976 under the assumption of generality among all stimulus conditions, aversive or otherwise, and as an explanatory model of human depression. This proposition allowed for some experimental manipulations aimed at reversing the effect, using, among others things, positive reinforcement during a \"therapy\" phase. With that in mind, the present research attempted to investigate whether: (a) animals that showed signs of helplessness in an escape test also show a learning deficit with positive reinforcement, whether or not involving stimulus control; (b) the exposure to positive reinforcement may cancel out helplessness and (c) helplessness interferes with resistance to change, measured during a second, positively reinforced, discrimination learning (reversal). Rats were first exposed to controllable (C), uncontrollable (I) or no shocks (N) and then to an escape test. Three groups (n=4) were selected: one that displayed helplessness (group I) and two that learned to escape (groups C and N). After that, all subjects were exposed to (1) positive reinforcement of lever pressing (shaping, CRF and ten sessions of discrimination between FR and extinction), (2) the same escape test, (3) ten sessions of discrimination learning with reversed discriminative stimuli. Other four animals were exposed only to sessions of positive reinforcement. All animals learned discrimination and reversal, and three out of four animals of group I remained helplessness in the second escape test. These results suggest that helplessness did not generalize to a positively reinforced task and that exposure to positive reinforcement did not cancel out helplessness for most subjects. Results are discussed considering the selective effect of helplessness, which occurs under some conditions, but not under all. The fact that therapy with positive reinforcement did not reduce the learning deficit observed with negative reinforcement suggest that if helplessness result from learning that it is impossible to control the environment, this knowledge does not include all stimuli in a generalized manner, but only one (or some) certain stimuli class. The identification of the characteristics that define these classes (electric shocks, aversive stimuli, among others) should also be the purpose of future research.
50

Alterações ambientais dependentes e independentes da resposta: uma investigação dos efeitos de contigüidade versus contingência / Response dependent and response independent environmental changes: a study on the effects of contiguity versus contingency

Nogara, Thaís Ferro 13 March 2006 (has links)
Made available in DSpace on 2016-04-29T13:17:56Z (GMT). No. of bitstreams: 1 Dissertacao Thais Nogara.pdf: 1558052 bytes, checksum: ccb32c051365bae930fde318c9580dd9 (MD5) Previous issue date: 2006-03-13 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The effects of presenting stimuli that are well established as reinforcers independently of responding have been studied under two different perspectives. On the first perspective, through a procedure called accidentally reinforcement, stimuli are presented non-contingently, resulting in the accidental selection of a response, an effect called superstition. On the other perspective, in a procedure called uncontrollability stimuli are presented independently of responding resulting in a difficulty in learning when another contingency is presented, a behavioral effect called learned helplessness (LH). It has been suggested that the interval from the non-contingent presentation of the stimulus and the response may have an important role in producing either one of two behavioral effects. The goal of this study was to investigate: (a) the effects of different duration of an aversive auditive stimuli on the possibility of establishing contiguity between responding and the ending of the stimulus; (b) the effects of the different stimulus-response intervals on the responding pattern; (c) the effects of different manipulations of stimuli presentation (response dependent, response independent, and delayed dependent) on the participants performances in a new escape contingency. Fifty participants were assigned to five groups: contingent (CON), yoked non-contingent (YNC), non-contingent (NC), contingent with delay (CD), and control. Four groups were exposed to two experimental phases: training and testing. In the training phase, each group experienced a different contingency: CON participants could escape from the aversive stimuli; YNC participants experienced the same aversive stimuli (order and duration) as CON participants, but could not escape; NC participants experienced 5s stimuli along the training phase and could not turn them off; CD participants could escape from the stimuli, but the emission of the response started a delay that was dependent upon the interval between the end of the stimulus and the preceding response emitted by a NC participant. The control participants were not exposed to a training phase. During test, all participants could escape from the aversive stimuli by emiting a new escape response. Results show that: a) 12 out of 40 participants showed some accidentally selected behavioral pattern during training. In the testing phase, all this 12 participants learned the new escape response. Other twenty-four participants had their performance in the testing phase classified as learned helplessness: 13 from NC and YNC groups, 4 from CON, 4 from control and 2 from CD; b) stimulus duration did not seem to determine the interval between the end of the stimuli and the preceding response; c) for some participants, temporal contiguity between the end of the stimulus and the preceding response was enough to select a behavioral pattern, but the contingent relation between these two events was a powerful variable in the selection and maintenance responding, even for those participants who were exposed to a contingent but not contiguous (delayed) stimuli-response relation / Os efeitos da apresentação independente das respostas de um sujeito de eventos ambientais bem estabelecidos como reforçadores têm sido investigados sob duas diferentes perspectivas. Para uma delas, a liberação não contingente desses eventos pode resultar na seleção acidental de respostas. O efeito em questão foi chamado de superstição e o procedimento, de reforçamento acidental. Sob uma outra perspectiva, a apresentação de estímulos independentemente do responder pode levar a uma dificuldade de aprendizagem quando uma nova contingência é apresentada. O efeito comportamental observado foi chamado de desamparo aprendido e o procedimento, de incontrolabilidade. Tem sido sugerido que o intervalo de tempo entre a apresentação não contingente do estímulo e as respostas dos sujeitos pode desempenhar um papel importante na produção desses efeitos. O objetivo do presente estudo foi investigar: (a) os efeitos de diferentes durações de um estímulo sonoro aversivo sobre o intervalo de tempo entre o seu término e a resposta precedente; (b) os efeitos desses diferentes intervalos sobre o responder dos participantes; e (c) os efeitos de diferentes arranjos experimentais (dependente, independente e dependente com atraso) sobre o desempenho dos participantes numa nova contingência de fuga. Para isso, 50 participantes foram distribuídos em seis grupos: contingente (CON), acoplado não contingente (ANC), não contingente (NC), contingente com atraso (CA) e controle. Quatro desses 5 grupos foram submetidos a duas fases experimentais: treino e teste. No treino, cada grupo passou por uma contingência diferente: ao grupo CON era dada a possibilidade de escapar do estímulo aversivo; o grupo ANC recebia os mesmos sons (mesma ordem e duração) que os participantes do grupo CON, mas não podiam escapar dos mesmos; o grupo NC experienciou sons com a duração de 5s durante toda a fase de treino e não podia desligá-los; o grupo CA podia fugir dos sons, mas a emissão da resposta de fuga iniciava um atraso que era determinado pelo intervalo entre o término do som e a resposta precedente, para o grupo NC. O grupo controle não passou pela fase de treino. No teste, todos os participantes podiam escapar dos sons por meio de uma nova resposta de fuga. Como resultado, observou-se que: a) 12 dos 40 participantes tiveram algum padrão de respostas acidentalmente selecionado no treino. No teste, esses 12 participantes aprenderam a resposta de fuga. O responder de outros 24 participantes, no teste, foi classificado como desamparo aprendido: 13 são dos grupos NC e ANC, 4, do grupo CON, 4, do grupo controle e 2, do grupo CA; b) a duração do som não foi a variável determinante do intervalo de tempo entre o término do som e a resposta precedente; c) embora, para alguns participantes, a contigüidade temporal entre o término do som e a resposta precedente tenha sido condição suficiente para selecionar um dado padrão de respostas, a relação de dependência entre esses eventos pareceu desempenhar um papel muito importante na seleção e manutenção do responder, mesmo para aqueles participantes expostos a uma relação estímulo-resposta contingente, mas não contígua (atrasada)

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